librc: Don't include stacked runlevels in ls_dir with LS_INITD.

ls_dir is used to list services in a runlevel, in which directories are
stacked runlevels, not init scripts. And in general, folders are not
allowed in init.d dirs anyway.

src/librc/librc.c

@@ -93,7 +93,8 @@ ls_dir(const char *dir, int options)
 				xasprintf(&file, "%s/%s", dir, d->d_name);
 				r = stat(file, &buf);
 				free(file);
-				if (r != 0)
+				/* stacked runlevels are not init scripts */
+				if (r != 0 || S_ISDIR(buf.st_mode))
 					continue;
 
 				/* .sh files are not init scripts */